Process of making heptaldehyde and undecylenic acid



atented Nov. 29, 1932 HERMAN A. BRUSDN, OF GERMANTOWN, PENNSYLVANIA, ANDJACK D. ROBINSON, F AUDUBON, NEVJ JERSEY, ASSIGNORS TO THE BESINOUSPRODUCTS 60 CHEMICAL CO. INC., OF PHILADELPHIA, PENNSYLVANIA PROCES$ OFMAKING HEPTALDEHYDE AND UNDECYLENIC ACID N0 Drawing.

This process relates to an improved method for making heptaldehyde andundecylenic acid from Castor oil by destructive distillation.

According to previous processes, castor oil or an ester of r'cinoleicacid is heated with or without catalysts, preferably under reducedpressure, at temperatures around 400 C. and the distillate therefromfractionated. The yield of heptaldehyde is usually small and its costhigh if castor oil is employed, as about 50 to 75 percent of the oilgoes over into an infusible, insoluble, spongy mass having no practicalvalue. It is removed only'with difliculty from the stills and representsan economic loss.

The object of the present invention is to prepare lreptaldehyde andundecylenic acid from castor oil in good yield without the formation ofthe above mentioned insoluble spongy mass; and to accomplish this in amanner more economical and more adapted for large scale manufacture thanprevious processes.

' We have discovered that heptaldehyde and undecylenic acid may beobtained in good yield by destructively distilling in vacuo a mixture ofcastor oil and an acidic resin such as colopliony, gum dammer, kauri,Congo, copals, ester gums and the like, without formation of infusible,insoluble, spongy still residues. The still residues obtained accordingto our process are fluid while hot and are readily run out from thestill. They constitute a useful by-product from the operation, thuscutting down the overhead costs of the heptaldehyde.

We are aware that in the past, castor oil has been heated with variousresins to obtain fluid compositions which areeither simple solutions ofthe resin in the oil or esterlike combinations of the acidic resin andthe oil. Such processes have been carried out at relatively lowtemperatures so thatno appreciable cracking of the castor oil to formeptaldehyde occurs. The essential features of our process are that theheating of the castor oil and resin is carried out at temperatures inexcess of the decomposition point of the castor oil so as to formheptaldehyde and Application filed May 9, 1931. serial No. 536,304.

undecylenic acidwhich may be condensed, and at the same time to preventformation of an insoluble, worthless still residue by taking up thestill residue as fast as it forms in a suitable gum or resin so that itmay be run out. 4

For practicing this invention the following examples are given. Theparts given are by weight.

Example 1 Raw cast-or oil (2 parts) is mixed with 1 part of wood rosinin a capacious still fitted with an inlet capillary tube for aspiratingair or an inert gas such as nitrogen or carbon dioxide through the mass.The still is con nected to a downward condenser attached to awater-cooled receiver which is in turn connected to a vacuum pump. Thestill is heated to about 400-450" C. so that the temperature of thecontents is 30O 340 C. and the distillation is carried out under apressure of from 30 to 60 mm. of mercury until no further distillatecomes over in the receiver. During this process air, nitrogen, or carbondioxide is continuously bubbled through the hot mass in, the still. Thedistillate obtained contains rosin, rosin oil, heptaldehyde, water, andundecylenic acid together with polymers of undecylenic acid. Theheptaldehyde and undecylenic acid may then be recovered from thisdistillate by suitable fractionation in the usual way. The still residuedue to its fluid nature is readily run out while hot and the stillrecharged for the next run. The still jresidue forms a solid rubber-likemass readily soluble in benzene and having potential com- Example 2Instead of rosin, an equal weight of ester, gum (acid No. 8) (abieticglyceride) may be used in the procedure described above at a temperatureof 330-340 C, -Heptaldehfde and undeylenic acid are obtained toget erwith a fluid still residue which is not as rubbery as that obtained inExample 1.

, Example 3 Castor oil is mixed with 25 percent of itsweight of kaurigum and subjected to destructive distillation at 340 C. under 50 mm.pressure is described in Example 1, to obtain heptaldehyde andundecylenic acid.

Instead of the above resins one may use other acidic gums, both naturaland synthetic, such as dammar, Congo, and the various copals or thecondensation products thereof with phenols and aldehydes.

Furthermore mixtures of any two or more of the above acidic gums orresins maybe employed in the condensation with castor oil, and pressureshigher or lower than that indicated may be employed during thedestructive distillation. Additional catalysts for accelerating thedecomposition may also be added in small amounts up to 2% by weight onthe oil. These inc ude acidic and basic substances such as limemagnesia, zinc oxide, boric oxide and phosphoric acid.

What we claim is:

1. A process for making heptaldehyde and undecylenic acid whichcomprises vacuum structively distilling a mixture of raw castor oil andester gum under vacuum at a temperature of 300-340" C. and condensingthe vapors.

HERMAN A. BRUSON. JACK D. ROBINSON.

tures.

distilling a mixture of castor oil and an acidic resin to inhibit thecondensation of the castor .oil to an insoluble mass," at a temperatureabove the decomposition point of the castor oil, and condensing thevapors.

. 2. A process for making heptaldehyde and' undecylenic acid whichcomprises distilling a mixture of raw castor oil and an acidic'resinunder vacuum at a temperature above the decomposition point of thecastor oil, and condensing the vapors.

3. A process as set forth in claim 2 in which one of the groupconsisting of air and inert gases is aspirated through the mixtureduring the distillation. 1 i

4. As a new composition of matter the still residue by-product resultinfrom the manufacture of heptaldehyde an undecylenic acid as set forth inclaim 2, said material being a benzene-soluble plastic mass.

5. The process for making heptaldehyde and undecylenic acid whichcomprises yacuum distilling a mixture of-raw castor oil a d a member ofthe group consisting of colophony, ester gumgdammar, kaur'i, Congo,copals, and mixtures thereof, at a temperature above the decompositionpoint of castor oil, and condensing the va ors.

6. Theprocess for ma ing heptaldehyde and undecylenic acid whichcomprises distilling raw castor oilwith one half its wei ht .ofrosinundervacuum at a temperature 0 300' 340 C. and condensing the vaors.

7. The process for making eptaldehyde and undecylenic acid whichcomprises de-

